The present application relates to prion deactivation. It finds particular application in conjunction with the deactivation of prion infected materials from medical and surgical instruments and will be described with particular reference thereto. However, it is to be appreciated that the present invention will also find application in conjunction with the decontamination of other surfaces contaminated with prion infected material such as pharmaceutical preparation facilities, food processing facilities, laboratory animal research facilities including floors, work surfaces, equipment, cages, fermentation tanks, fluid lines, and the like.
Prions are proteinaceous infectious agents which cause similar fatal brain diseases, known as transmissible spongiform encephalopathies (TSEs). These diseases include Creutzfeldt-Jakob disease (CJD) in humans, Bovine Spongiform Encephalopathy (BSE) in cattle, also known as “mad cow” disease in humans, Scrapie in sheep, and Wasting disease in elk and deer. These diseases are characterized by initially long incubation times. Once neurological signs, such as dementia or loss or coordination, become apparent, relatively rapid neurological degradation follows leading to death. The prions are believed to be an abnormal form of a protein commonly found in the host. However, unlike the normal form of the protein, the host is unable to break down the abnormal form. The abnormal proteins accumulate, particularly in neural tissue, eventually causing neural cell death.
Although not considered to be highly contagious, prion diseases can be transmitted by certain high risk tissues, including the brain, spinal cord, cerebral spinal fluids, and the eye. After a surgical procedure on a prion infected patient, prion containing residue may remain on the surgical instruments, particularly neurosurgical and opthalmological instruments. During the long incubation period, it is extremely difficult to determine whether a surgical candidate is a prion carrier.
Prions are very resistant to deactivation. Unlike microorganisms, prions have no DNA or RNA to destroy or disrupt. Prions, due to their hydrophobic nature, tend to aggregate together in insoluble clumps. Under many conditions that lead to successful sterilization in microorganisms, prions form tighter clumps which protect themselves and underlying prions from the sterilization process. The World Health Organization (1997) protocol for prion deactivation calls for soaking the instrument in concentrated sodium hydroxide or hypochlorite for two hours followed by one hour in an autoclave. This process is, of course, damaging to many medical instruments and destructive of others.
The present application provides a new and improved prion deactivation technique which overcomes the above-referenced problems and others.